Backstroke rhymes with:
keystroke, masterstroke, keystroke, masterstroke, keystroke, ladbroke, masterstroke, pembroke, artichoke, countryfolk, gunsmoke, holyoak, holyoke, keystroke, ladbroke, masterstroke, pembroke, roanoke, slowpoke, townsfolk, vanderkolk, windhoek, woolfolk
Backstroke sounds like:
babysitters, backdoors, backstairs, backtrack, backtracks, backwaters, bacteria's, bastarache, baxter's, boisterous, bookstores, booster's, boosters, busters